<template>
	<a-cascader
		v-bind="attrs"
		:options="options"
		:load-data="loadData"
		change-on-select
		@change="handleChange"
		:displayRender="handleRenderDisplay"
	>
		<template #suffixIcon v-if="loading">
			<LoadingOutlined spin />
		</template>
		<template #notFoundContent v-if="loading">
			<span>
				<LoadingOutlined spin class="mr-1" />
				数据加载中...
			</span>
		</template>
	</a-cascader>
</template>
<script lang="ts">
import { defineComponent, PropType, ref, unref, watch, watchEffect } from 'vue';
import { Cascader } from 'ant-design-vue';
import { isFunction } from '@/utils/is';
import { get, omit } from 'lodash-es';
import { LoadingOutlined } from '@ant-design/icons-vue';
import { useAttrs } from '@/hooks/core/useAttrs';

interface Option {
	value: string;
	label: string;
	loading?: boolean;
	isLeaf?: boolean;
	children?: Option[];
}
interface RenderDisplay {
	labels: Recordable[];
	selectedOptions: Recordable[];
}
export default defineComponent({
	name: 'ApiCascader',
	components: {
		LoadingOutlined,
		[Cascader.name]: Cascader,
	},
	props: {
		api: {
			type: Function as PropType<(arg?: Recordable) => Promise<Option[]>>,
			default: null,
		},
		numberToString: { type: Boolean as PropType<boolean>, default: null },
		resultField: { type: String as PropType<string>, default: '' },
		labelField: { type: String as PropType<string>, default: 'label' },
		valueField: { type: String as PropType<string>, default: 'value' },
		childrenField: { type: String as PropType<string>, default: 'children' },
		asyncFetchParamKey: { type: String as PropType<string>, default: 'parentCode' },
		immediate: { type: Boolean as PropType<boolean>, default: true },
		// init fetch params
		initFetchParams: {
			type: Object as PropType<Recordable>,
			default: () => ({}),
		},
		// 是否有下级，默认是
		isLeaf: {
			type: Function as PropType<(arg: Recordable) => boolean>,
			default: null,
		},
		displayRenderArray: {
			type: Array,
		},
	},
	emits: ['change', 'defaultChange'],
	setup(props, { emit }) {
		const apiData = ref<any[]>([]);
		const options = ref<Option[]>([]);
		const loading = ref<boolean>(false);
		const emitData = ref<any[]>([]);
		const isFirstLoad = ref(true);

		const attrs = useAttrs();

		watch(
			apiData,
			data => {
				const opts = generatorOptions(data);
				options.value = opts;
			},
			{ deep: true },
		);

		function generatorOptions(options: any[]): Option[] {
			const { labelField, valueField, numberToString, childrenField, isLeaf } = props;
			return options.reduce((prev, next: Recordable) => {
				if (next) {
					const value = next[valueField];
					const item = {
						...omit(next, [labelField, valueField]),
						label: next[labelField],
						value: numberToString ? `${value}` : value,
						isLeaf: isLeaf && typeof isLeaf === 'function' ? isLeaf(next) : false,
					};
					const children = Reflect.get(next, childrenField);
					if (children) {
						Reflect.set(item, childrenField, generatorOptions(children));
					}
					prev.push(item);
				}
				return prev;
			}, [] as Option[]);
		}

		async function initialFetch() {
			const api = props.api;
			if (!api || !isFunction(api)) return;
			apiData.value = [];
			loading.value = true;
			try {
				const res = await api(props.initFetchParams);
				if (Array.isArray(res)) {
					apiData.value = res;
					return;
				}
				if (props.resultField) {
					apiData.value = get(res, props.resultField) || [];
				}
			} catch (error) {
				console.warn(error);
			} finally {
				loading.value = false;
			}
		}

		async function loadData(selectedOptions: Option[]) {
			const targetOption = selectedOptions[selectedOptions.length - 1];
			targetOption.loading = true;

			const api = props.api;
			if (!api || !isFunction(api)) return;
			try {
				const res = await api({
					[props.asyncFetchParamKey]: Reflect.get(targetOption, 'value'),
				});
				if (Array.isArray(res)) {
					const children = generatorOptions(res);
					targetOption.children = children;
					return;
				}
				if (props.resultField) {
					const children = generatorOptions(get(res, props.resultField) || []);
					targetOption.children = children;
				}
			} catch (e) {
				console.error(e);
			} finally {
				targetOption.loading = false;
			}
		}

		watchEffect(() => {
			props.immediate && initialFetch();
		});

		watch(
			() => props.initFetchParams,
			() => {
				!unref(isFirstLoad) && initialFetch();
			},
			{ deep: true },
		);

		function handleChange(keys: any, ...args: any[]) {
			emitData.value = keys;
			emit('change', keys, ...args);
			emit('defaultChange', keys, ...args);
		}

		function handleRenderDisplay({ labels, selectedOptions }: RenderDisplay) {
			if (unref(emitData).length === selectedOptions.length) {
				return labels.join(' / ');
			}
			if (props.displayRenderArray) {
				return props.displayRenderArray.join(' / ');
			}
			return '';
		}

		return {
			attrs,
			options,
			loading,
			handleChange,
			loadData,
			handleRenderDisplay,
		};
	},
});
</script>
